Gut-associated bacterial microbiota in paediatric patients with inflammatory bowel disease

Abstract

Background: Clinical and experimental observations in animal models indicate that intestinal commensal bacteria are involved in the initiation and amplification of inflammatory bowel disease (IBD). No paediatric reports are available on intestinal endogenous microflora in IBD. Aims: To investigate and characterise the predominant composition of the mucosa-associated intestinal microflora in colonoscopic biopsy specimens of paediatric patients with newly diagnosed IBD. Methods: Mucosa-associated bacteria were quantified and isolated from biopsy specimens of the ileum, caecum and rectum obtained at colonoscopy in 12 patients with Crohn's disease, 7 with ulcerative colitis, 6 with indeterminate colitis, 10 with lymphonodular hyperplasia of the distal ileum and in 7 controls. Isolation and characterisation were carried out by conventional culture techniques for aerobic and facultative-anaerobic microorganisms, and molecular analysis (16S rRNA-based amplification and realtime polymerase chain reaction assays) for the detection of anaerobic bacterial groups or species. Results: A higher number of mucosa-associated aerobic and facultative-anaerobic bacteria were found in biopsy specimens of children with IBD than in controls. An overall decrease in some bacterial species or groups belonging to the normal anaerobic intestinal flora was suggested by molecular approaches; in particular, occurrence of Bacteroides vulgatus was low in Crohn's disease, ulcerative colitis and indeterminate colitis specimens. Conclusion: This is the first paediatric report investigating the intestinal mucosa-associated microflora in patients of the IBD spectrum. These results, although limited by the sample size, allow a better understanding of changes in mucosa-associated bacterial flora in these patients, showing either a predominance of some potentially harmful bacterial groups or a decrease in beneficial bacterial species. These data underline the central role of mucosa-adherent bacteria in IBD.

Microbiota of De-Novo Pediatric IBD: Increased Faecalibacterium Prausnitzii and Reduced Bacterial Diversity in Crohn's But Not in Ulcerative Colitis

“…Furthermore, the organisms least likely to be aff ected would be those with adherent properties, of most interest in the mucosal disease of IBD. In support of our approach, other investigators have demonstrated diff erences in the IBD microbiota despite prior bowel preparation ( 10,29 ). Finally, a study design where children undergo diagnostic colonoscopy under general anesthetic without adequate preparation would be ethically unacceptable.…”

Ribonucleotide Reductase NrdR as a Novel Regulator for Motility and Chemotaxis during Adherent-Invasive Escherichia coli Infection

“…Most E. coli strains isolated from the ileal mucosa of CD patients are able to adhere to and invade intestinal epithelial cells (14)(15)(16) and belong to the pathogenic group of adherent invasive E. coli (AIEC) (17). AIEC is highly associated with the ileal mucosa in CD patients (14)(15)(16)(18)(19)(20)(21)(22)(23). CD-associated AIEC cells adhere to the brush border of primary ileal enterocytes isolated from CD patients but not to enterocytes isolated from controls without inflammatory bowel disease.…”

Antibiotic Exposure and Juvenile Idiopathic Arthritis: A Case–Control Study

“…12,13 At least 1 category of JIA has been associated with distinct intestinal microbial populations. 14 Antibiotics can alter some subjects' intestinal microbiota for $6 months.…”